Creating A Matrix For Magic Square Project

I am making a program that reads a set of numbers (e.g.: 8 1 6 3 5 7 9 4 2) and prints them into a matrix.For example:

8 1 6 3 5 7 9 4 2, will produce:
8 1 6
3 5 7
9 4 2

When taking in these numbers from the user, I am not allowed to let the user state what size the matrix is (e.g.;3 x 3). Instead the program needs to determine that itself. I have written the code below to count the number of numbers inputted, but now I am stuck as to how to get them into the array. I have what is suppose to be my array written, but it is not function yet.

import java.util.*;
public class MagicSquare {
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);

[code]....